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Re: tree-ssa: a weird (mis)optimization
- From: Geert Bosch <bosch at adacore dot com>
- To: Andrew Haley <aph at redhat dot com>
- Cc: gcc at gcc dot gnu dot org
- Date: Tue, 30 Nov 2004 13:09:53 -0500
- Subject: Re: tree-ssa: a weird (mis)optimization
- References: <16812.39590.439732.460777@cuddles.cambridge.redhat.com>
On Nov 30, 2004, at 11:07, Andrew Haley wrote:
The problem here is that the line
<tmp>_4 = x_3->length;
has disappeared. This should not have happened, because the operation
should have may_trap_p() set -- we're deleting a trapping instruction.
Does Java require a trap here, even if the result is not needed
and the entire expression could otherwise be deleted? For other
languages such as C and Ada, it is fine to delete the instruction,
even if it would be trapping.
If Java prevents such removal, we should find a way to express
that so other languages don't lose the optimization.
-Geert